The present invention relates to an adjustable profiling head for a wood cutting apparatus, such as for use in log and lumber processing in a lumber mill.
In order to produce squared lumber from a log, curved or wany edges of the log must be removed. To optimize the number of boards that can be obtained from the log, boards of optimum size are identified that will substantially fill the cross-sectional area of the log, leaving a number of such wany edges. A profiling apparatus is used to cut or chip away the wany edges, and this may be done before the boards are sawed from the log. Particularly, the profiling head cuts a corner that extends along the length of the log and that defines an outer side of one board and at least part of the upper or lower face of an adjacent board. To cut the corner, the profiling head rotates about an axis and has at least one set of first knives oriented at right angles to one another.
The speed of the profiling operation is increased if the wany edges for a number of boards can be removed by the same profiling head. A profiling head that can be used to cut away two wany edges at one time has at least one additional set of knives. The knives of the additional set are disposed a different radial distance from the axis of rotation than the first knives and are displaced axially therefrom as well.
For example, the first knives may be used to cut a first corner defined by an outer side of a first board and at least part of the upper face of a second board that lies beneath and extends beyond the first board. The additional knives may simultaneously be used to cut an adjacent corner defined by an outer side of the second board and at least part of the upper face of a third board that lies beneath and extends beyond the second board. The difference in radial positioning of the first knives relative to the additional knives, as well as the difference in axial positioning of the first knives relative to the additional knives, may define either the thickness of one of the boards or the difference in width between two adjacent boards. The absolute positioning of all of the knives of the profiling heads used to profile the log, in concert with the positioning of the profiling heads themselves, defines the dimensions of board lumber sawn from the log.
Examples of adjustable profiling heads are found in Dietz, Disclosure Document DE 44 19 324 (xe2x80x9cDietzxe2x80x9d) and Linck, European Patent Application No. 96107714.6 (xe2x80x9cLinckxe2x80x9d). Dietz discloses an outer corner milling machine and an inner corner milling machine, each resembling a pot, one lying at least partially within the other. Each of the corner milling machines is adapted to cut a corner and is equipped for this purpose with a cleaver on the circumference surface and a plane blade oriented at right angles to the cleaver. xe2x80x9cAdjustment unitsxe2x80x9d are used to adjust the axial spacing between the two corner milling machines. The xe2x80x9cadjustment unitsxe2x80x9d are not described, but appear to be electric motors. Radial adjustment is not provided, and axial adjustment appears to require feedback control of the motors to find and maintain a command spacing. This spacing can change as a result of the forces encountered by the milling machines and at least some time will be required for the controller and feedback mechanism to restore proper spacing, resulting in imprecise cutting.
Linck discloses a milling head having a large diameter ring of cleavers and a smaller diameter ring of cleavers. The cleavers have their cutting edges aligned with the axis of revolution of the milling head. The cleavers are attached to cleaver carriers which are fastened with screws to respective cleaver supports. The radial disposition of the cleaver supports can be adjusted by loosening the screws. The cleaver supports can also be moved in axial rails within the carriers and can be locked in at different axial positions with terminal blocks and screws. Disksaw segments are installed between the cleavers in the smaller ring. These are stated as being adjustable but no means for adjusting the disksaw segments is disclosed. Moreover, while the position of the cleavers can be adjusted both axially and radially, holding the cleavers in position depends on frictional forces exerted by tightening screws, so that there is no provision for positively locking the position of the cleavers.
Accordingly, there is a need for an adjustable profiling head for a wood cutting apparatus that provides for radial or axial adjustment of the position of knives mounted to the profiling head as well as positive and secure locking of a selected position of the knives.
The invention disclosed herein is an adjustable profiling head for a wood cutting apparatus. Within the scope of the invention, there is a first body portion for carrying a plurality of first knives and a second body portion for carrying a plurality of second knives. The cutting edges of the knives define respective cutting surfaces of revolution about an axis that have different mean diameters for the two body portions. In one aspect of the invention, the body portions are adapted to receive the respective knives by associated knife clamping mechanisms that are adapted to be removably mounted to the body portions with one or more first control plates therebetween, for adjusting the radial positioning of the knives. In another aspect of the invention, the body portions are adapted to be removably mounted to each other so that the body portions are disposed axially adjacent one another with one or more second control plates therebetween, for adjusting the relative axial positioning of the knives of one of the body portions with respect to the knives of the other body portion.
Therefore, it is an object of the present invention to provide a novel and improved adjustable profiling head for a wood cutting apparatus.
It is a further object of the present invention to provide an adjustable profiling head for a wood cutting apparatus that provides for radial adjustment of the position of knives mounted to the profiling head.
It is still a further object of the present invention to provide an adjustable profiling head for a wood cutting apparatus that provides for axial adjustment of the position of knives mounted to the profiling head.
It is yet a further object of the present invention to provide an adjustable profiling head for a wood cutting apparatus that provides for both radial and axial adjustment of the position of knives mounted to the profiling head.
It is another object of the present invention to provide an adjustable profiling head that provides for positive and secure locking of a selected position of the knives.
The foregoing and other objects, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the following drawings.